Sheet handling and feeding apparatus



March 23, 1937. v. T. GROVER 2,074,339

SHEET HANDLING AND FEEDING APPARATUS Filed Sept. 22, 1933 9 Sheets-Sheet 1 ATTORNEYS March 23, 1937. v. T. GROVER SHEET HANDLING AND FEEDING APPARATUS Filed Sept. 22, 1933 9 Sheets-Sheet 2 ATTORNEY5 March 23, 1937. v. T, GROVER SHEET HANDLING AND FEEDING APPARATUS 9 Sheets-Sheet 4 Filed Sept. 22, 1935 x v g m ATTQRNEY6 9 Sheets-Sheet 5 V. T. GROVER Filed Sept. 22, 1933 SHEET HANDLING AND FEEDING APPARATUS March 23, 1937.

'vl r wwem ATTORNEY5 V. T. GROVER SHEET HANDLING AND FEEDING APPARATUS March 23, 1937.

Filed Sept. 22, 1955 9 Sheets-Sheet 6 oR'NEYs March 23, 1937.

Filed Sept. 22, 1933 V. T. GROVER SHEET HANDLING AND FEEDING APPARATUS 9 Sheeis-Sheet 7 IN ENTOR #7 ATTORNEY5 March 231 1937.

V. T. GROVER SHEET HANDLING AND FEEDING APPARATUS 9 SheetsSheet 8.

Filed Sept. 22, 1953 4 1 ill J AINVENTOR Vlifi- "FM '17" ATTORNEY March 23, 1937. v GRQVER 2,074,330

SHEET HANDLING AND FEEDING APPARATUS Filed Sept. 22, 1933 9 Sheets-Sheet 9 a I l 1:

' Ill! "i" INVENTOR V BYMP ATTORNEYS Patented Mar. 23, 1937 l lTED SHEET HANDLING 1.

APPARATUS Application September 22, 1933, Serial No. 690,626

16 Claims.

The present invention relates to an apparatus for handling sheet material such as tin plate and the like, and has particular reference to apparatus for separating and feeding sheets from a stack which is placed in the machine and brought to feeding position, certain mechanism elevating the stack to present the top sheet to the separating devices and to maintain the top of the stack in feeding position, the operations being automatic and insuring proper feed while per mitting insertion of other stacks of sheets to the end that time losses will be minimized.

The invention contemplates two different elevating functions for movement of the stack of sheets so that when a stack is first introduced into the machine, the elevator may be rapidly I actuated to bring the top. of the stack into its desired feeding-position, following which the elevation of the stack automatically continues at a relatively slow rate to correspond with the sheet removal time.

The elevating control of the apparatus prevents elevation of a stack beyond a predetermined position regardless of whether the rapid or the slower elevating movement is being employed. After a stop of the elevator under such stop control, operation is again automatically resumed as soon as the top of the stack is sufficiently lowered, this being brought about by the removal of the fed sheets. This control furthermore insures against a constant starting and stopping at each feeding cycle by introducing a time element which slows down and evens the elevating action.

An object, therefore, of the invention is the provision of an apparatus for sepai ating sheets in a stack and individually feeding them from off of the stack while maintaining the stack in proper feeding position.

A further object of the invention is the provision of suction devices for such an apparatus which individually engage and separate sheets from a stack and which also shake each sheet to further insure its full individual separation, the separated sheet then being fed laterally from the stack with the help of the suction devices.

The invention also contemplates the utilization of suction devices which are moved to persuction devices still hold the separated sheet and bodily move with it during its feeding, this insuring accurate control of the sheet at all times and until it is properly within the sphere of action of the feeding devices.

A further feature of the operation of the suction devices insurefs full and complete sheet engagement and where such engagement is defective the lateral removal of the separated sheet is withheld until the proper engagement is made.

Numerous other objects and advantages of the invention will be apparent asit is better understood from the following description, which, taken in connection with the accompanying drawings, discloses a .preferred embodiment thereof.

Referring to the drawings:

Figure 1 is a side elevation of a. sheet handling and feeding apparatus embodying the present invention;

Fig. 2 is a longitudinal section partly broken away looking toward the front of the machine, being taken substantially along the section line 2-2 in Fig. 1;

Fig. 3 is a front elevation of the apparatus broken away on one side;

Fig. 4 is an enlarged sectional view taken substantially along the broken line d4 in Fig. 3;

Fig. 5 is a plan, sectional suction cup air valve detail taken substantially along the line 55 in Fig. 4;

Fig. 6 is a plan sectional view of the magnetic feeding rollers, being taken substantially along the line 66 in Fig. 4;

Fig. 7 is a side elevation partly in section of one of the vibration suction cups;

Fig. 8 is an enlarged transverse sectional cletail taken substantially along the line 88 in Fig. 3;

Fig. 9 is an enlarged sectional detail of the elevator ratchet feed as taken substantially along the line 9-9 in Fig. 3;

Fig. 10 is a side elevation partly in section of one of the feeding suction cup members as taken substantially along the line I'll-l il in Fig. 3;

Fig. 11 isa sectional view of the magnetic rollers being taken substantially along the line il-ii in Fig. 6;

Fig. 12 is an enlarged plan sectional detail taken substantially along the line I 2-42 in Fig. 2;

Fig. 13 is.a wiring diagram of the motor elevator circuit and the electric control circuit for the apparatus;

Fig. 14 is a plan sectional view through the suction cup air valves as viewed along the section line |4|4inFig. 4;

Fig. 15 is a sectional view of the suction cup air valves being taken substantially along the line 5 |5|5inFlg.4;

, Fig. 16 is a plan sectional view taken substantially along the line |6-|6 in Fig. 1;

Fig. 1'7 is an enlarged sectional view of the elevator stop control as taken substantially along 10 the1ine|1-|'| inFig.3;

Fig. 18 is a fragmentary perspective view of a part of a conveyor chain and its stack supporting member; a

Fig. 19 is an enlarged side elevation of the elevator drive shown partly in section and showing substantially the same parts as are illustrated in the lower central section of Fig. 3; a

. Fig. 20 is a sectional detail taken substantially along the broken line 20-28 in Fig. 19; g 20 Fig. 21 is a plan view of one of the suction head shifting devices as viewed from along the broken line 2|2| in Fig. 8, parts being broken away; and

Fig. 22 is a sectional detail taken substantially 25 along the line 2222 in Fig. 3.

General construction The apparatus disclosed in the drawings as a preferred embodiment of the present invention is mounted upon a base 4| (Figs. 1 and 2) which supports two spaced side frames 42. Each side.

frame is formed by upwardly extending hollow columns 43 which are connected adjacent their upper ends by a double walled connecting section 44. The columns43 are connected adjacent their bottom ends by an angle iron 45 which ties the columns together adjacent their connections with the base 4| and provides supports for certain parts of the elevator mechanism.

The four vertical columns 43 of the two side members 42 are all connected together by a housing cover or casing 46 which ties the parts firmly together and provides a closed top for the two spaced side members. At the front part of the machine the forward columns 43 are further con nected adjacent their middle sections by a connecting plate 5| (Fig. 3) which is secured by bolts 52 to the columns.

A shelf member 53 is also disposed on the front of the machine, this shelf extending across and between the forward columns at a position near the base 4|, bolts 54 being used for this purpose. These members 5|, 53 (Figs. 1' and 3) also assist in providing a rigid construction for cer- 55 tain operating parts of the machine.

Stack elevator s a height of 12 or 14 inches.

In inserting a skid of stacked sheets into the apparatus, it is placed between the two side frames 42 being introduced through an open end and from the rear of the machine. The base 4| is formed centrally with vertically extending side plates 58, two of these extending up and in between the side frames 42, as best illustrated in I Hg. 2. A supporting fioor 6| of wood or other suitable material is first laid upon the top of the plates 58 and the skid of stacked tin plate is placed upon this floor and is then in position for elevation.

The elevator embodies a pair of elevating chains 65 (Figs. 1 and 2) located between the columns 5 43 of each side frame 42 and the chains operate 'over lower idler sprockets 66 and upper drive sprockets 61. Each sprocket 66 turns freely on a stub shaft 68 carried in a bracket 69 secured by. bolts II to the side of the angle iron 45. Each 10 bracket 69 may be slotted at 12 where the bolts 1 I extend through the bracket wall for adjustment purposes, such adjustments providing for tightening of the elevator chains.

The two drive sprockets 61 on each side of the 1 5 apparatus are secured to a drive shaft I5 (Figs.

1, 2, and 16) which is journaled in bearings I6 formed in a tubular sleeve section 11 joining the spaced walls of the connecting section 44 at its top. 20

Each of the chains 65 carries spaced blocks 8| (Figs. '1, 2, and 18), each block being secured to a link of the chain by pins 82 which pass through and form the pintles for the chain link. Two blocks 8| one of each chain-are connected to- 25 gether by means of a bar 83 which extends across the space between the chains and ties the chains together at spaced intervals.

As the bars pass to the inside of the chain run and move upwardly a pointed nose 84 formed on 9 one end of side strip extensions 85 of each block 8| passes into the lower end of a vertical groove 86 of a side strip 81 (Figs. 2, 12, and 16) which is formed with a tongue 88 which fits within a groove 89 cut in each column 43. The block side w strip extensions 85 slide freely within the grooves 86 but fit sufliciently close to steady the chains 65 and the bars 83.

Elevator motor drive and rapid lift 50 The elevator for first raising the stack of sheets 55 into feeding position is preferably operated for quick movement at which time an electric motor is used and after coming into position the sheets are then slowly raised in a step by step movement by other means. The first or rapid lifting of the stack prevents unnecessary loss of time in bringing the stack of sheets into feeding pos tion near the upper part .of the apparatus and the second or step feeding is used to hold the top of the stack into the proper sheet feeding position. This first or rapid drive of the conveyor will first be considered in detail.

Each conveyor shaft 15 (Figs. 1, 3, and 16) is extended toward the front of the machine where it passes into a gear' housing 8|. This gear housing is bolted to the front column 43 of each side frame 42. A worm gear 62 is keyed to the end 70 of each shaft 15 where it is confined within the housing and the shaft at this forward end is further journaled in bearings 83 formed in the housing. A cap 84 bolted on the outside of each housing at the end of the shaft confinesthe shaft 14 end and also a washer 95 and a lock nut 96, the latte'r threadedly engaged on the end of the shaft. Washer and lock nut prevent longitudinal shifting of the shaft.

Each worm gear 92 meshes with a worm 95 and the two worms are secured to the ends of a horizontal shaft 96. The shaft 96 is journaled at its ends in bearings 91 formed in the gear housings 9I and in bearings formed in tubular shells 98 bolted at 99 to the inner faces of the two gear housings. A housing cover I III is bolted to the outer side of each gear housing 9I and encloses the end of the shaft 96 on that side.

The shaft 96 carries a sprocket I05 (Figs. 1 and 3) over which operates a chain I06. Chain I96 also operates'over a lower sprocket I 91 (see also Figs. 9 and 19) which is preferably an integral part of a gear I08, the sprocket and geartu'rning loosely on a stud I09 held in a boss III of a bracket II2 mounted upon and supported by the shelf 53. .A nut I I3 threadedly engaging the end of the stud I99 holds it in fixed position.

The gear I08 (Fig. 1) meshes with a-gear II5' which is secured to a gear reduction shaft II6 also journaled in the bracket II 2 the end of the shaft extending into a gear reduction unit H1. The gear reduction unit also connects with and receives rotation from a motor shaft II8 (Figs. 3 and 19) of an electric motor II9 mounted upon and secured to the shelf 53.

This motor H9 is used to operate the elevator when it is raising a stack of sheets at the higher speed, the motor at such time being energized through an electric circuit which will be hereinafter more fully described. As long as the motor H6 is receiving its electrical energy, the shaft H8 is rotating and through the gear reduction N1 the shaft II6 is simultaneously rotated but at a slower speed.

By means of the gear and sprocket connections previously described, this rotation is transmitted to the shaft 96 as the higher speed of drive for elevating the gear reduction unit I I6 merely cutting down from the motor speed at such time. The shaft 96 in turn, by means of the worm gearing 95, 92, operates the shafts 15 and the chains 65 to rapidly lift the skid 56 with its stack of sheets 55. i

The need for this rapid raising of the sheets in the elevator ceases as soon as sheet feeding position is reached and the motor I I 9 is thereupon deenergized and its driving ceases. The parts are now driven by the slower, step movement mechanism which will now be described.

Elevator ratchet drive and step by step lift The elevating chains 65 on this step by step operation are also driven through the motor shaft II8 but at such time the shaft is not rotated by the motor but is turned freely within the motor. For this purpose the motor shaft I I 8 between the motor and the gear reduction unit II1 carries a ratchet I25 (Figs. 3, 17, and 19) which on one side is against one face of the gear reduction unit and on the opposite side extends into a sleeve I26.

-The sleeve I26 terminates in a threaded reduced end I21 on which is threadedly mounted a I26 of the ratchet and at some times slide rela- 'tive to the sleeve I26.

The ratchet I25 is moved in a step by step movement during the slow feeding of the elevating. conveyors by means of a dog I35 (Fig. 17) having a toothed projection I36 which engages in one,of the teeth of the ratchet. is pivotally mounted on a pin I31 which is carried in a flanged wall I38 (Figs. 1'1 and 20) extending outwardly from the sleeve. I3I.

The flange I36 also carries a win ItI which provides a pivotal connection for an adjustable connecting rod unit M2, the upper end of which is formed with a head I43 (Figs. 3, 9, and 19) which extends over a crank pin- I44 projecting outwardly from the face of a crank disc I45. The crank disc I65 is secured to one end of a horizontal shaft M6 which is jcurnaled in bearings I41 formed in the frame plate 5I.

The opposite end of the shaft I66 carries a sprocket I5I (see also Fig. 1) which is located at one side of the machine. A chain I52 operates over the sprocket I5I and also over an idler sprocket I53 loosely mounted on a stud I58 carried in the end of a bracket I 55. The bracket I55 is mounted upon and secured to one'of the gear housings M. The chain I52 also passes over a sprocket I56 which is secured to a shaft I51 also journaled in the bracket I55.

The chain I52 also passes over and is driven by a sprocket I6I which is secured to one end of a horizontal drive shaft I62 located near the top of the apparatus. Shaft I62 is journaled in bearings I63 formed in upwardly extending projections I69 of the cover casing 46. The drive shaft I62 is continuously rotated in any suitable manner as by the application of power to a drive pulley I65 secured to the opposite end of the shaft and this rotation continues as long as the machine is operating.

When the elevating chains are being operated at the rapid lifting speed by means of the motor II9 as previously described the drive shaft I62 continues to operate the crank I45 and through the crank connection described continues to oscillate the sleeve I3I. The motor shaft H8 at such time, however, is turning at a much greater speed of rotation than the sleeve and the teeth of the ratchet I25 snap by the teeth I36 of the dog I35.

The flange I38 of the sleeve I3I also carries a stud I1I (Figs. 9, 19, and 20) on which a spring dog I12 is pivotally mounted. This dog is held in engagement with the teeth of the ratchet I29 by a spring I13 which is interposed between the free end of the dog and a screw eye I14 threadedly engaging the sleeve I3I.

Each shifting of the sleeve I3I in one direction I (counterclockwise, Fig. 9) moves the ratchet disc I29 the distance of a tooth and in the other direction the dog I12 slips back over and engages the next adjacent tooth of the ratchet disc. Since the disc I 29 is disclosed with eight teeth, eight oscillations of the sleeve I3I will carry the ratchet disc I29 through one complete rotation on the sleeve.

The ratchet disc I29 carries a pin I 8| which loosely supports a roller I82 adapted to operate a. switch associated with the stopping of the elevator. The electric circuit in which this switch is embodied is also associated with a second switch that in its turn is operated when the top of a stack of sheets has reached a predetermined position. This will now be described in detail.

Elevator stop switch and electric controls When the top of a stack of sheets within the elevator reaches the predetermined positionre- The dog I35 ferred to, the uppermost sheet engages and raises a roller 26I (Figs. 1 and 7) rotatably mounted on' an arm 252 pivotaily secured at 262 to a bracket 265 secured to and carried by a horizontal stationary supporting shaft 265 carried'in the frame of the machine. This stationary shaft extends across the machine at its rear end and is carried in the cover casing 46, being held in bearings 266.

The arm 252 is formed with a boss 251 with which a rod 266 is associated, the upper end of the rod being formed with a slotted head 206 which engages a pin 2 carried in an arm 2I2 of an electric switch 2I2. This switch 2|! toi gether with the switch operated by the roller "I on the ratchet disc I26 is used to stop lifting of the sheets by the elevator. Such control is effective during the time the motor II! is raising the sheet stack rapidly and also-during the time i the step by step feeding of the sheets is being carried out by' operation of the drive shaft I62 through the ratchet device described in the last section.

Reference should now be had to Fig. 13 which aovasso motor and causes its actuation. As soon as the but before it is lifted, this being graphically indi- 30 an electric circuit directly associated with the motor H9 and when so closed permits lifting of the stack through the conveyors at the rapid rate. With switch 2|3 in this position the motor II9 is started for the rapid-lifting of the sheets by the pressure. of a starting button 2I5. The starting button is contained in a suitable switch box and a stop button 2I6 is also contained in the same box. The current passes through the motor circuit'when the starting button is operated. 40 The electric motor II! is preferably connected in a three-phase electrical system comprising lead wires 0., b and c which preferably pass through a suitable service switch 2" and thence into a switch box designated by the dot and dash lines and marked 2I6. This switch box may also contain, the start and stop buttons 2I5, 2I6 previously referred to. .In the diagram of Fig. 13 these buttons are indicated diagrammatically as outside of the outlines of the switch box, this arrangement making the diagram less complicated.

A wire 01 leads from one side of the starting button switch 2I5 and connects with the wire 0 the opposite side of the switch being connected by a wire e to an automatic four-contact switch I one point of which is joined by a wire g to the motor Ill.

An electro-magnet 2I9 is carried in the switch box 2|6 and is associated'by a movable solenoid core or similar device with the switch embodying I the contact points f. This switch is a spring back or normally opened switch. The magnet is joined by a wire it to the wire 12 and by a wire-k leading from the switch 2|3. A return wire 1 leads from the opposite side of the switch 2I3 to one side of the stop button switch 2I6.

When the start button 2I5 is moved to close the circuit through the motor II! a momentary starting current flows from the wire 0, wire d through the starting and stop switches 2|5, 2I6,

wire I, switch 2I3, wire it and into the electromagnet 2i! and wire it back to the lead line b. This energizes the electro-magnet 2|! and closes the automatic switch at contacts I. leading the current into the electric motor IIQ.

' The current thereupon passes through wire 0 and wire a and through wires 0, b and through wires m, 11 leading respectively from the. wires a, b and such a current excites the fields of the automatic switch closes at the contact points I a new circuit is established and current follows the same path as the starting current only now it passes along the wire e and thence back to c.

The start button 2I5 is not included in this holding circuit and its immediate release by the operator in no way ailects the continued operation of the motor. As long as the current flows in this manner the motor operates and the conveyor raises the stack of sheets at the rapid lifting rate. This continues until thecurrent is broken at switch 2I3 which takes place when the grail) of the stack of sheets lifts the switch roller The starting circuit and the holding circuit for the motor II! which has Just been described, is not used in any way for automatically stopping the elevators when they are being raised slowly .through connection with the drive shaft I62 but the same switch 2I3 is used at such a time for opening another independent control circuit associated with the ratchet I25 and the. ratchet disc I29, this circuit being also disclosed in diagram in Fig. 13.

The actuation of the elevator in its step movement and through the ratchet I25 takes place only when the dog I35 is in engagement with the tooth I36 of the ratchet during movement of the sleeve |3I on its feeding stroke. Engagement between ratchet and dog is brought about by the energizing of a solenoid 225 (shown in detail in Fig. 19) which is suspended from the shelf 53 directly beneath the ratchet I25.

A core 226 of the solenoid 225 extends upwardly through an opening in the shelfand carries a pin 22'! on which a roller 226 is rotatably mounted. This roller extends within an arcuate groove or slot 225 (see also Fig. 9) formed in one face of the dog I35. As long as the solenoid 225 is energized its core 226 is held in raised position and the end of the dog I35 engages the periphery of the ratchet I25, this being the position of Figs. 9 and 17. o

On the other hand, if the solenoid 225 is deenergized a spring 23I (Fig. 19) contained within the solenoid and bearing against the enlarged lower end of its core 226, forces the core into lowered position. and pulls out the dog I35 from its engagement with the ratchet.

Whether or not the solenoid 225 is energized depends in turn upbn the position of the roller I82 can-led by the ratchet disc I29. As disclosed in Fig. 9 this roller I62 in one position engages a roller 215 carried orPan arm 236 of a switch 251 which is. mounted on the shelf 53 beneath the ratchet disc I25, this being adjacent the solenoid 225. The action of the solenoid and the switch 221 will now be explained in connection with the wiring diagram ofFig. 13.' i

With the switch 2I3 closed current forthe control circuit flows from any suitable source of supply such as a generator 2 through a wire 0, through the closed switch 2i: and wire 1) and a .wire q, the coil of the solenoid 225 and thence by a wire 1' through a lamp s and wire t backto the other side of the generator 2. This energizes the solenoid 225 and raises its core 226 and moves the vdog I55 into feeding position. This movement is against the action of the solenoid spring III.

, stop the elevator.

55 high stack position immediately stops rapid eleaovasao As soon as the core 226 moves into this raised position, a second circuit is closed through a switch 242 contained within the bottom of the solenoid 225. Figure 19 shows this switch in detail, it being enclosed within a cover plate 243 amxed to the solenoid. The lower end of the core 226 projects down and engages one of the contact points of the switch when the core is in lowered position and at such time the circuit in the switch 242 is broken. The contact points of this switch, however, normally spring into closed position when the solenoid core 226 is raised.

One side of the switch 231 is electrically connected with the switch 242 by a wire u and the opposite side is connected by a wire '0 with the wire p at its junction with the wire q. The opposite side of switch 242 is connected by a wire w with the wire 0. Such an arrangement operates as follows.

When the roller I82 is out of engagement with the switch roller 235 of the switch 231 the latter is closed through its wires u, vand as soon as the switch 242 is closed a secondary circuit flows from the wire 0, switch 242, wire u, switch 231, wire 1),

wire q through the winding of the solenoid 225,

high position until the roller I82 engages the roller 235 of the switch 231. At that time the current is interrupted and step lifting of the stack of sheets ceases.

The eifect ofthis combination of circuits is to prevent a stop of the lifting action of the elevator merely when the top of the stack opens the switch 2I3 by engagement with the roller 201 of the switch except at such time as the switch 231 is also opened. This means in an extreme case where the roller I82 has just passed by the switch roller 235 that the elevator will continue to operate in its step movement, even though thetop of the stack opens the switch 2I3, until the ratchet disc I29 is moved through its seven remaining step positions.

Opening of the switch 231 at the end of that time, however, (the switch 2I3 remaining open) will disengage dog I35 and ratchet I25 and thus It-will be observed that a vation but step elevation may be delayed.

Sheet separation suction cups When the top of the stack of sheets is about touching or is in engagement with the switch roller 20I, the top sheet of the stack is in position for engagement by the suction devices. These suction devices comprise two rear suction heads 25I and two' front suction heads 252 (Figs.

1, 3, 4, and 15) The two rear heads are supported on the stationary shaft 205 (see also Fig. 7) each head body having an extension 253 which rests on top of the shaft 205 and which is held in clamped position bya clamping plate 254 se- 70 cured by bolts to the part 253. This holds the two 75 gaging part of the suction device has vertical movement within the cylinder. Each movable rear suction device is provided with a suction rub ber or suction cup 255 which is held in the bottom end of a movable block 256, a screw 251 having a flat head being threadedly engaged in the block for this purpose.

The movable (block 256 is threadedly engaged in the lower end of a piston 258, the upper end of which slidably fits within the cylinder suction head 25I. The lower part of the piston is smaller in diameter and this feature provides a chamber 259 between the inside wall of the cylinder and the exterior wall of the piston. Piston 258 is formed with a hollow central chamber 261 and the block 256 and screw 251 are both centrally apertured to provide communication between'the chamber 26! and the inside of the suction rubber 255.

The chambers 259, 261 are joined by radial ports 264 which are utilized in the removal of air from within the suction cup 255 when it has engaged the top sheet 55 in the stack. A port 265 out radially through the suction head body 25I and opening into the chamber 259 allows for removal of the air from the chamber as will be hereinafter more fully described.

The piston 258 of each rear suction head is adapted to move downwardly from the raised position of Figs. 4 and 15 into the position of Figs. 1 and 7, and this movement is effected by the use of vacuum. The suction head body 251 is provided with a second radial port 266 located in alignment and above the port 265 and the combined use of atmospheric pressure and vacuum is -made in connection with the passageways 265,

266 for such piston movement. A detailed description of this feature will be reserved for subsequent explanation in connection with the suction control valves.

Thetwo rear suction cups 255 coming down and engaging the. top sheet in the stack lift the rear edge of the sheet as they again move upwardly. In a similar manner the sheets front edge is moved upwardly by means of suction cups associated with the front suction heads 252, as will be hereinafter described in detail.

The two rear suction devices embodying vibrating features by means of which the rear edge of the engaged top sheet is vigorously shaken after it has been lifted clear of the stack, this vibrating action tending to shake loose and separate any adhering sheets. A separate vibrating unit is associatedwith each rear suction head for this purpose.

The upper end of the cylinderhead 25I is closed by a second piston 21I (Figs. 4 and 15) which also has sliding airtight fit within the cylinder, this piston also being hollow and open at its top. A transfer pin 212 extends diametrically across this opening and provides a pivotal support for the lower end of an am 213 which is formed at its upper end with an eccentric strap form of head 214 mounted on an eccentric collar 215 carried on a motor shaft 216 of a small electric motor 211. Each motor 211 is supported on the stationary shaft 205 being mounted upon a bracket 218 which rests on and is held in fixed stationary position by a clamp 219 bolted to the bracket.

Continual rotation of the motor 211 acting through the eccentric collar 215 and arm 213 causes its associated piston 2" to move up and down through a small distance but at a very rapid rate. When the piston 258 is in the upper position within the cylinder 9. disc 2!" carried in the top of this piston holds against the lower end of the piston 2 and the rapid movement of the latter is communicated as hammer blows to the suction rubber 255. The shaking loose of any adhering sheets is further assisted by an air.blast di- 6 rected against the sheet edges, as will be hereinafter more fully described.

Each front suction head 252 is bolted to and carried on a projecting part 20| (Figs. 4 and 10) of an arfn 292. This is near the lower end of the 10 am (see also Fig. 2) and its upper 'end is keyed to a rock shaft 293 mounted on top of the apparatus and positioned adjacent and parallel to the drive shaft I62. Each arm 292 is also formed 1 with a split section 204 where it is closed around the shaft and is held in its fixed position by a bolt 295. The rock shaft 293 is journaled in bearings 206 (Figs. 1 and 2) projecting upwardly from the cover casing 46.

Each suction head 252 like the rear head m is formed as a hollow cylinder which is closed at the top by a plate (Figs. and 15). The lower end of this cylinder carries a hollow piston 302. This piston at its lower end carries a suction rubber or cup 303 which is secured by a threaded 25 screw 3 to a cup head 305 which is held by the same screw to a plug 306 pinned in the lower end of the piston 302.

The screw 304 is centrally apertured at 301 which provides an opening between the inside of the suction cup and a chamber 308 inside of the hollow piston 302. The upper end of the piston 302 is enlarged and slidingly fits within the cylinder head 252, its smaller lower end leaving a A space between the piston wall and the cylinder wall as a chamber 309. A small port 3|0 provides a connection between the chambers 308, 309. A chamber 3 is formed in the space above the piston 302 and connects with a radial bore 3| 2 cut through the wall of the head 252 to provide one'connection with the vacuum and air valve which will be hereinafter more fully described. A similar radial bore 3|3 is also cut through the cylinder wall and communicates with the chamber 303 and this is a second connection with the vacuum and air valve.

The lifting of the forward end of the top sheet by the two suction cups 303 is done while the suction heads 252 remain in vertical position (Fig. 4) The piston 302 moves up into the cham- 0 her 3 until a button 3|5 formedon its top end strikes against a cushion disc 3I6 carried in the lower end of an upper piston 3" located in the upper endof the suction head cylinder. The piston 3|1 at such time is in the position illus- 55 trated in Fig. 4. 5 v

The piston 3" is hollow and is enlarged at its 1 upper end-to fit within a chamber 32| in the suction head 252 just beneath the cap 30|. 'Ihe upper end of the piston is internally threaded to receive a disc 322 which forms a top for the piston. vides acentral chamber 323 and'a plug.324 is located in the chamber. The plug is of slightly 1 smaller diameter than the diameter of the cham- 5 her and is less in height than the height of the chamber.

Plug 324 is carried on the lower end of an adlusting screw 325 which extends loosely through an opening in the disc 322 and which is threadedly secured in the cover "I. Turning of this screw within the cover adjusts the vertical position of the plug 324 and 'when adjusted the same is held in fixed position by a lock nut 326 threadedlythe upper end of the screw. A

' 7s packingwasher m is clamped between the lock The hollow space in the piston 3" pronut 326 and the top of the cover 30| and makes an airtight joint aroundv the thread.

, When the piston 302 is in its lowered or sheet engaging position the upper piston 3" is held suspended from the screw :25, the disc 322 rest ing on the upperend of the plug. When the piston 302 moves up with the sheet and it's"upper button end 3|5 strikes against the seat 3|6 the impact is sufllcientto raise the piston 3" until the bottom wall of the chamber 323 strikes against the bottom of the plug 324;

This slight movement acts as a buffer for the rapidly moving piston 302 and permits a quicker movement of piston without an excessive shock.

-An air port 33| cut through the cylinder wall of the suction head directly below the enlarged part of the piston 3" allows for a restricted escape of air from below the head of the piston and lets it return to lowered position gently and without striking.

With the sheet held in raised position by the rear suction cups 255 and the front suction cups 303, it isin position to be, moved forward or laterally of the stack. Before considering such a movement, however, the valve controlling the operation of the pistons 258, 302 for the suction cups 255, 303 will be considered.

The suction cup valves Each rear suction device is controlled by two connections with the suction valve whereas each forward suction device utilizes three valve connections. This valve comprises a valve body or cylinder block 35| (Figs. 4, 5, 14, and 15) which is bolted to the cover frame 46. This valve body is provided with five vertically disposed cylindrical bores 352 each of which provides a chamber for an independent valve. Each chamber 352 at itsbottom end is closed by a plug 353 inserted into and secured to the valve body 35L apparatus.

A valve 36| acts as a piston in each chamber 352, having an airtight sliding fit therein. Each valve isrecessed at its bottom end at 362 and each plug 353 is similarly recessed at 363, the two recesses being in vertical alignment. A spring 364 is located in each chamber 352, its ends extending into the recesses 362, 363 and normally holding its associated valve 36| in'raised position, this position being disclosed in Fig. 4.

The valvebody 35| on the side opposite to the manifold 354 is recessed to provide an airtight seat for avalve plate 31.| (Figs. '4, l4, and 15) which projects rearwardly and extends into an opening 312 out through the wall of the cover 46. This plate 3" is secured-to the valve body by screws 313 and is provided with five hollow projections 314, 315, 316, 311. and 313 which extend out through the opening 312. Each of these projections 'encloses'a chamber 36L A chamber as: is formed in the plate :1! it the base of each chamber 33| and two small airpassages 363, 384 are cut through the wall of the ber connects with the source of vacuum, when lowered, with atmosphere.

Each valve 36! is formed with an annulargroove 39!. When the valve is in raised position this annular groove provides a connection between the port 383 and a second port 392 is cut through the wall of the valve body 35! directly opposite. At such a time air is withdrawn from the chambers 38!, 382 through the port 383, annular groove 39l, port 392 and vacuum cham- 0 ber 355 and out through the vacuum pipe 356.

When the valve is depressed or in its lower position its annular groove 39! is in register with the lower port 384 of the chamber 382 and with a second port 393 cut through the front wall ofthe valve body 35! directly below the manifold 354 and opposite to the port 384. In this position air passes into the port 393, valve groove 39!, port 384, chamber 382 and into the chamber 38!. Each chamber 38! communicates with one or the other of the suction devices 25!, 252 and the connecting ports or chambers accordingly are either on vacuum or atmosphere according to the condition of its valve chamber 38!.

As best illustrated in Fig. 15 the two rear suction devices 25 connect on one side or the other,

that is, on the top or bottom of the hollow projections 311, 318. The particular suction heads 25! and 252 shown connect on the bottom of the projections and the two suction heads not shown connect on top. {the port 266 formed in the suction head 25! is connected by a pipe 48! with the hollow projection 318 and the port 265 is similarly connected by a pipe 482 with the hollow projection 311.

In like manner the front suction heads 252 are connected with the hollow projections 314, 315, and 316. Each port 3!.3 is connected by a pipe 483 with the projection 314 and the port 3!2 is connected by a pipe 484 to the projection 315. A

5 third port 486 is cut 'through the cap 38! and communicates with the chamber 32! and this port is connected by a pipe 481 with the projection 316.

The operation and timing of the suction devices 25!, 252 will be considered in detail, it being only necessary to operate the valve 36! associated with the desired chamber 38! to supply the particular suction with atmosphere or with vacuum, according to the work to be performed.

Prior to this detailed consideration,.however, the mechanical operation of the valves 36! will be considered.

Each valve spring 364 holds its valve 36! in raised position where its associated suction head is on vacuum and such valve is depressed to cut off the vacuum connection and bring about atmospheric conditions by a cam controlled arm 4!5 (Figs. 3, 4, 5, and 15). Each arm is centrally bifurcated and its sides at one end merge into a boss 4!6 which is loosely mounted on a horizontal stationary shaft 4" held in bearings 4!'8 of a pair of projections 9 extending forward from the valve body 35!.

The free or opposite end of the arm. 4!5 engages the top of the valve 36! and when the latter is in its raised position a tall 425 formed in each boss 4! 6 strikes against a tie rod 426 extending between and carried in projections 4!9. This limits the action of the Valve spring 364. A cam roller 421 (Figs. 3, 4, and 5) is rotatably mounted on a pin 428 which holds its roller between the walls of the arm M5, the pin 428 being supported in these arms.

Each valve is independently controlled by a cam 43l which is located on and keyed to the drive shaft 162, the five cams being located alongside. A cam acting on the roller 421 rocks the arm M5 on the shaft 4H and pushes the valve 36! downwardly against the action of its spring 364 to bring the annular valve groove 39! in register with the ports 384, 393 and establish at mospheric conditions in the connecting pipe line, as previously described.

The rear suction cups 255 first engage the sheet to be fed and to obtain this action the upper ports 266 of the suction heads 25! are opened to atmosphere by the depression of the valve 36! (Fig. 4) associated with the valve projection 318 (Fig. 15). Air thereupon flows into the port 393 through the annularvalve groove 39!, port 384, chambers 382, 38!, pipe 48!, port 266 into the upper end of the chamber containing the piston 258, this being above the top of the-piston.

Gravity drops the pistons 258 but at the same time vacuumis'efiected through the valve projection 311 and this assists gravity in lowering the cups 255. Air is drawn out of each chamber 259 in each valve body 25! through the port 265,

pipe 482, chambers 38!, 382, port 383, annular valve groove 39!, port 392, vacuum chamber 355 and thence out through the vacuum pipe 356.

The piston descent is rapid under the atmospheric pressure exerted on its upper end and the suction rubber 255 is brought firmly into engagement with the uppermost sheet 55 in the stack. The edges of the suction rubber seal on the sheet and air is quickly drawn out from the space within the rubber and over the surface of the sheet. This creates a suction hold between rubbers and sheet so that the latter can be safely raised with the lifting of the piston 258.

Piston 258 is immediately raised, this being accomplished by removal of air from the upper end of the piston while the suction still obtains in the center of the piston. Raising of the depressed valve 36! of the valve extension 318 changes the interior of the cylinder heads 25! from atmosphere to vacuum and air passesout from the top of the piston 258 through the port 266, pipe 48!, etc., back to the vacuum line 356. With vacuum on the top part of the piston as well as in the chambers 259, 26! the atmospheric pressure exerting itself from under the held sheet forces the two pistons 258 upwardly, thus lifting the sheet at its rear end into the position illustrated in Fig. 4.

In a similar way the two forward suction heads are conditioned by means of their valves 36! so that the piston 382 of each is lowered to bring its suction rubber 383 into engagement with the front part of the top sheet on the stack. This is done in the following manner.

Air is drawn out of the chamber 389 (Figs. 4 and 15) of each suction head 252 through their ports 3!,3, pipes 483 and. chambers 38!, 382 of the extension member 314 and thence out through the port 383, the annular valvegroove 39!, port 392 and vacuum chamber 355. Air also passes 10 The weight of the piston assisted by atmospheric pressure from above, and with the chamber 309 vacuumized from below carries the pie-- ton down and brings its rubber 303 into sheet engagement. As soon as the edges of suction rub- 15 bers 303 have sealed against the sheet the space beneath the rubbers and above theengaged part of the sheet is vacuumized as was previously done with the rear suction cups 255. Air in this space now passes out through the port 301 in the screws 304, out of the chamber 308 through the port 3l0 into the chamber 303, and thence out into the vacuum line. This action holds the sheet against the rubbers and permits lifting with the raising of the two pistons 302. s

' To effect thelifting of the piston 302 the valve 30! associated with the valve extension 315 is shifted from its atmosphere setting. and the chamber 3!! is vacuumized. With air removed from the top of the piston and with its inside chamber vacuumized, the atmospheric pressure exerting itself from the under surface of the engaged sheet raises the pistons 302, rubbers 303 and thefront edge of the sheet. This lifting of the pistons 302 may take place about the same time as the lifting of the pistons 258 or it may be at a different time as desired.

The air blasts associated with the rear suction heads previouslyreferredto will now be considered. Figs. 3, 4, and 22 disclose the nozzle,

40 pipes, etc., used for this purpose. The air is controlled by a valve so that it is only delivered as used and under pressure and as a relatively strong blast. The air is turned on as soon as the sheet reaches its raised position. A discharge nozzle 45 44! (Fig. 4) is supported in a holder 442 ad- Compressed air is brought to the pipe 45! at D 53 all times and a sliding valve 452 located in the valve body controls connection through the valve between the pipes 446, 45!. When the valve 452 is depressed communication between the pipe 446 and the source of compressed air in the pipe 45! C is cutoff and it is only when the valve 452 is raised that compressed air is permitted to enter through the pipe 446 and to be delivered into the nozzles 44! The valve 452 is raised in proper time to eflect this discharge of air through the nozzles by means of a cam carried on the drive shaft I62. The valve 452 carries 'a valve stem 455 formed with a head 456. A lever 451 .is pivotally mounted at 458 to an extension 459 of the bracket 448 and one 70 end of the lever engages beneath the head 451 of the valve stem. Thetopposite end of the lever carries a cam roller 46! which rides against the periphery of a cam 462 mounted on the drive shaft !02. This cam is so formed as to depress 75 the roller 46! and rock the lever 451 to. lift the latch 415.

valve 452; at which time the desired air blast is delivered through the nozzles.

Suction cups sheet feed The sheet 55 which has just been lifted and separated from the stack of sheets is ready for transfer laterally from its position over the stack. This is accomplished by a swinging of the forward suction heads 252 while the sheet is still vacuumization of the upper chambers 32! through I the valve in the valve extension 318. The vacuum is still held on the chambers 308, 309, 3! l, as each chamber 32! is vacuumized. Air from this chamber passes through the port 406, pipe 401 and chambers 30!; 382 ofthe valve extension 316 and thence into the vacuum chamber 355.

As soon as air has been exhausted from the top of each of the pistons 3" the later move upwardly, atmosphere at such time passing through the radial port 33! of each to a lower surface of the piston and the air under the engaged sheet also assists and the piston 302 is correspondingly raised. The plug 324 limits this upward move-' ment, the bottom wall of the piston 3l1 striking against the bottom of the plug. This is only a slight movement but is enough for the unlatching action.

During this short lifting movement of each piston 302 its sucker head 305 has been brought into engagement with two arms of .a yoke 41! (Figs. 3, 4, and which partially surrounds 'each piston 302and is secured to the bottom end of a sliding rod 412. This rod moves through a lug 413 projecting outwardly from the cylinder body 252 of each front suction device and its upper end is pivotally connected at 414 (see also Fig. 8) to a The latches hold the front suction devices in vertical fixed position during the time their suction heads are engaging a sheet.

Each latch 415 is pivotally connected at 416 to the lower end of each arm 202 and each latch when in latched position engages a stationary bar 411 which extends across the front of the machine, its ends being secured to the housing cover 46. l-Iioth of the-front suction heads 252 must be unlatched from this bar 411 before the rock'shaft 203 supporting the arms can be moved and this provision insures against shifting the sheet unless both of the suction rubbers 303 are fully engaged. I a

If only one rubber holds them the latch 415 associated with the other suction head is not lifted suiliciently to disengage the bar 411 as the piston 302 will not raise if air passes into the suction cups and no swinging movement of the suction heads is possible. In the event, however, that both suction rubbers 303 properly engage the front of the sheet and both pistons 302 are raised the extra distance to lift the yokes 41!, both latch members 415 are disengaged and the arms 292 are free to move as soon as rocking movement is applied to the rock shaft 293. This rocking of the shaft will now be described.

The rock shaft 293 adjacent its center carries an arm 405 (Figs. 3, 8, and 21) which is loosely mounted on the shaft. This arm is extended at its rear in a tall section 436 which acts as a guide for the arm in its movement over or with the shaft 293. When either or both of the front suction head arms 292 are held against movement, the arm 485 moves loosely over the shaft 293, but when both of the latch members 415 are disconnected from the bar 411 this arm moves with the shaft.

This-is made possible by the use of a block 48'! which is split into two side sections 488 that I extend along each side of the tail part 486 of the arm 485. Each side section is mounted on the shaft 293 and one or both are keyed to the shaft as at 489. One of the side sections is split at 49I and a bolt 492 is threadedly secured in the section and spans the slit 49I clampingthe block 481 securely on the shaft. 1

The block 481 extends upwardly and is apertured for'the reception of a threaded bushing 495 in which a bolt 498 is slidably disposed. The bolt 498 is pivotally connected at 498 to the arm 485 and its end outside of the bushing is threaded to receive a nut 499. A spring 50! surrounds the bolt 496 and is interposed between the inner end of the bushing 495 and a head section of the bolt.

The arm 485 carries a roller 502 which is ro tatably mounted on a pin 503 carried on the free end of the arm. This roller operates in a cam groove 504 formed in a face cam 505 (Figs. 3, 8,

' and 21) keyed to the drive shaft I82. For each cycle of operation, that is, for one complete revolution of the drive shaft I62 the am 485 isrocked and in the event that the latch members 415 prevent movement of the arms 292 and the shaft 293, the bolt 495 is pushed outwardly .through its bushing .495 without moving the block 481 or the shaft 293 on which it is keyed.

In the event, however, that the latch members 415 are lifted to disengage the bar 411 movement 40 of the am 485 is transmitted to the block 481 and the shaft 293 is rocked to move the arms 292 and carry the suction device heads 252 forward or toward the right as viewed in Fig. 4.

During this forward movement of the sheet with the suction heads 252 the suction is released from the rear suction rubbers 255 by a proper valve change from vacuum to atmosphere through the pipe 402. and as soon as the rear edge of the sheet is shifted laterally past the rear suction rubbers they are brought down on the remaining stack of sheets and hold their positions until the forward edge of the sheet has been moved into magnetic rollers and the suction on the suction rubbers 303has been released. The arms 292 then return the front suction heads 252 into their latched position.

' Magnetic roller feed The forward edge of the sheet comes into positionontop of a series of magnetic rollers 5I5 (Figs. 3, 4, and 6) keyed on a horizontal shaft M8. The shaft 5I6 is journaled at its' ends in bearings 5" formed in the lower part of the I cover frame 46. Seven rollers 5I5 are disclosed in the drawings and between each roller the shaft 5I8 is further journaled in magnetic housing 5I8 (Figs. 4, 6, and ll).

, These ma netic housings are bolted to the rear face of an angle iron 5I9 which extends 7 'across and connects two roller side frames 52I. A second forward angle iron 522 located parallel to the angle iron 5I9 also connects the side frames together. Each side frame MI is extended rearwardly in a supporting base 523 75 which is bolted at 524 to the cover frame 45.

Each of the magnetic casings 5I8 contains a bushing 53I in which the shaft 5I5 freely rotates. This bushing is held securely in the easing and is surrounded by a magnetic coil 532 which sets up a magnetic field on the ends of the coil, which field envelops the rollers 5I5 and magnetizes these rollers. The forward edge of the sheet as it is brought over these rollers is magnetically attracted to the rollers by the combined magnetic action of the rollers themselves and also the magnetic field surrounding the easings 5I8 and this holds the sheet against the rollers asv the latter advance it forward and out of the machine.

In this movement the sheet rides over supporting plates 535 which are mounted upon spacing blocks 535 formed in the angle irons 5G9, 522, these plates providing a track for the sheet. As the forward edge of the sheet passes over and beyond the forward angle iron 522 it engages a second set of magnetic rollers 53! which are mounted upon a horizontal shaft 538 journaled at its ends in bearings 539 formed in the side frames 52 I. This shaft is also journaled in inter mediate magnetic casings 54I which, like the casings 5I8, are formed with bushings 542 surrounded by magnetic coils 543 which create a magnetic condition in the rollers 531 similar to that of the rollers 5I5.

The sheet in its passage over the plates 535 and rollers 515, 531 is held to a straight line of travel by the magnetic influence of the rollers which prevent any slipping of the sheet, both of the shafts 5I6, 538 being positively rotated in unison to effect the proper feeding of the sheet.

A sprocket 55I (Figs. 4 and 6) is keyed to the shaft 5I5 and a sprocket 552 (see also Fig. 3) is keyed to the shaft 538 and these sprockets are operated in unison by a chain 553. A chain tightener sprocket 554 is loosely carried on a stud 555 carried on a bracket 555 bolted to the angle frame 5!!! and maintains the chain 553 in proper working order.

The shaft 538 is the driving shaft for the rollers and for this purpose carries a gear 56I (Figs. 1, 3, and 6) keyed to its end. The gear 56I meshes with a gear 552 secured to the end of the stub shaft I51 opposite to its sprocket pinion I55. Rotation of the shaft I51 through the sprocket I55 and the chain I52, previously described, eifects the proper rotation of the drive for the feeding rollers 5I5, 531.

It is thought that the invention and many of its attendant advantages will be understood from the foregoing description, and it will be apparent that various changes may be made in the form, construction and arrangement of the parts without departing from thespirit andscope of the invention or sacrificing all of its material advantages, the form hereinbefore described being merely a preferred embodiment thereof.

I claim:

1. A sheet handling and feeding apparatus, comprising in combination, an elevator for receiving and raising a stack of sheets, feeding devices for individually removing sheets from said stack, pairs of suction devices arranged over opposite edges of the top sheet, and air blast means cooperating with a pair of suction devices, means.

for inserting a second stack of sheets into said elevator while the sheets in said first stack are being fed by said feeding means, means for moving said elevator gradually, and means for moving said elevator rapidly.

2. A sheet handling and feeding appar t comprising in combination, an elevator for receiving a stack of sheets, actuating means for said elevator for receiving a stack of sheets, actuating means for said elevator for rapidly raising the stack, other actuating elevator means independent of said first means for raising the stack at a slower rate of travel, and means for inserting a second stack of sheets into said elevator while said first stack is being raised thereby, and pairs of suction devices arranged over opposite edges of the top sheet, and air blast means cooperating with a pair of suction devices.

3. A sheet handling and feeding apparatus, comprising in combination, an elevator for receiving a stack of sheets, actuating means for rapidly raising the stack by operation of said elevator to bring the sheets into feeding position, other actuating means independent of said first means for raising the stack at a slower feeding rate of travel to hold said sheets in substantial feeding position, feeding devices for individually removing said sheets from said stack consisting of pairs of suction devices arranged at opposite vices for individually removing sheets from said stack consisting of pairs of suction devices arranged at opposite edges of the top sheet, means for inserting a second stack of sheets into said elevator while the sheets in said first stack are being fed by said feeding means, means for stopping the lifting action of said elevator when the top sheet in said first stack is in its feeding position, and means controlled by the first stack for subsequently bringing the sheets in said other stacks into feeding position following the removal of sheets from the preceding stack.

5. A sheet handling and feeding apparatus, comprising in combination, an elevator embodying a plurality of chains having supporting members for holding a stack of sheets, actuating means for moving said chains to rapidly raise said supporting members with their superimposed stack of sheets, and other actuating means for moving said chains to raise said supporting members and said stack at a slower rate of travel.

6. A sheet' handling and feeding apparatus, comprising in combination, an elevator embodying a plurality of chains having supporting members for holding stacks of sheets, actuating means for moving said chains to continuously raise said supporting members with a said stack of sheets, other actuating means for also moving said chains to intermittently raise said supporting members with said stack, and means for selectively operating one or the other of said actuating means, said chains lowering said supporting members on the downward runs of the chains and carrying them out of the path of travel of the sheets being lifted by said elevator.

'7. A sheet handling and feeding apparatus, comprising in combination, anelevator for raising a stack of sheets, means for inserting a second stack of sheets into said elevator and below said first stack while the same is being lifted, and automatic means for stopping the lifting action of said elevator at predetermined intervals, the

elevation of the second stack being controlled after the removal of the first stack.

8. A sheet handling and feeding apparatus, comprising in combination, an elevator for lifting a stack of sheets in a step by step movement, an electric switch opened by the stack of sheets reaching a certain vertical position, and devices operating at predetermined intervals for stopping said elevator when said electric switch is opened.

9. A sheet handling and feeding apparatus, comprising in combination, an elevator for lifting a stack of sheets and for holding the top of said stack in feeding position, suction devices for engaging the top sheet in the stack and for raising and separating it from the other sheets, means for shaking a said suction device and the sheet engaged thereby to free the latter from the sheets in the stack, conveying means mounted adjacent said stack, and means for shifting other of said suction devices to carry said separated sheet to said conveying means.

10. A sheet handling and feeding apparatus, comprising in combination, suction devices for removing the sheet from a stack of sheets, pneumatic means for moving said devices into engagement with said sheet and for raising it, pneumatic means for shaking said engaged sheet to separate it from the other sheets in the stack, conveying rollers mounted adjacent said stack, and means for shifting a said suction device to carry said separated sheet to said conveying rollers.

11. A sheet handling and feeding apparatus, comprising in combination, two sets of suction devices for engaging the top sheet in a stack of sheets, one set raising one end of the top sheet and separating it from the other sheets by shaking it above the stack, the other set of said suction devices engaging and raising the opposite-end of the top sheet, conveying means mounted adjacent said stack, and means for shifting the latter set of said suction devices to carry said separated sheet to said conveying means.

12. A sheet handling and feeding apparatus, comprising in combination, two pairs of suction devices for engaging the top sheet in a stack of sheets, a said pair for engaging each end of the top sheet, conveying means mounted adjacent said stack, and means for rocking one pair of said suction devices on a stationary axis to carry said top sheet to said conveying means when each suction device of said pair is in engagement with said sheet.

13. A sheet handling and feeding apparatus, comprising in combination, supporting members for holding a stack of sheets, a pair of suction devices for engaging one end of the top sheet in the stack of sheets and holding it by suction means for raising said pair of devices with the said top sheet and separating the sheet from the other sheets, a latch associated with each suction device for locking it against lateral and shifting movement, means operative upon full suction engagement of a said suction device for releasing its latch, conveying means mounted aifiacent said stack, and means for shifting said suction devices to carry said separated sheet to said conveying means when both of said suction device latches are released.

14. A sheet handling and feeding apparatus, comprising in combination, two sets of suction devices for engaging the top sheet in a stack of sheets, one set raising one end of the top sheet and separating it from the other sheets by shaking, the other set of said suction devices engaging and raising the opposite end of the top suction devices to carry said separated sheet to said conveying means, and means for preventing said shitting movement of said suction devices in the event that the sheet is not properly engaged thereby. v

15. A sheet handling and feeding apparatus, comprising in combination. suction devices for engaging and lifting the top sheet in a stack of sheets to separate it froni the other sheets, conveying rollers mounted adjacent said stack, magnetic means for magnetizing said rollers, and 4 means for moving a said suction device laterally to bring said separated sheet into the magnetic influence of said conveying rollers.

16. A sheet handling and feeding apparatus, comprising in combination, suction devices for engaging and lifting the top sheet in a stack of sheets to separate it from the other sheets, conveying rollers mounted adjacent said stack, magnetic means for magnetizing said rollers, and means for shifting a said suction device to position said separated sheet above said rollers and within the magnetic influence of said conveying m1lers.

VICTOR T. GROVER. 

